FWHM

@staticmethod
def evaluate(waveform: WaveformVariable) -> float:
    """
    Calculate the FWHM of a waveform. Errors if image or scalar provided.

    First, applies smoothing by taking weighted nearest and next-nearest
    neighbour contributions to  y values whose difference from their neighbours
    is more than 0.2 times the total range in y.

    The global maximum y value is then identified along with the first
    positions to either side of the peak where the y value is less than or
    equal to half the global maximum. If all y values to one side of the peak
    are greater than half the global maximum, the position of the global
    maximum is used. The difference between the values of x at these two
    positions is returned.
    """
    half_max_left, half_max_right = Builtin.calculate_fwhm(waveform)
    return half_max_right - half_max_left